Hi,

I'm sorry I misunderstood your problem. I tried it by doing some testing and I was able to reproduce the error.

I created a SQL account and granted all but sysadmin rights. When taking a backup by clicking through the GUI, I got the error message when clicking on button [...] to browse for a location (just as you said).

I used Profiler Trace to see what was going on and found the GUI executes stored procedure "xp_fixeddrives". The error is generated because "exec xp_fixeddrives" doesn't return any records when executed by a non-sysadmin account.

I don't think your problem can be solved without giving the login explicit "sysadmin" rights. There are ways to execute the stored procedure with sufficient rights (see: http://serverfault.com/questions/82314/how-can-i-give-a-sql-server-user-permission-to-run-one-stored-procedure-and-noth) but that will not work with the GUI.